1. Field of the Invention
The present invention relates to a printing web position adjusting apparatus capable of adjusting a side edge position and a position in a travelling direction, that is, cutoff position, of printing web travelling in a rotary press.
2. Description of the Related Art
As apparatus for adjusting a side edge position of printing web travelling in a rotary press, for example, apparatus disclosed in Japanese Patent Publication No. Hei 6-29108 and Japanese Patent No. 2743200 are publicly known.
First, the apparatus disclosed in Japanese Patent Publication No. Hei 6-29108 is constituted by upstream side and downstream side fixed guides provided in parallel with each other at an interval of a certain distance therebetween in a travelling direction of printing web (hereinafter, may be referred to as xe2x80x9ctwo fixed guidesxe2x80x9d) and upstream side and downstream side guide bars provided at an interval of a certain distance therebetween in the travelling direction of the printing web (hereinafter, may be referred to as xe2x80x9ctwo guide barsxe2x80x9d). The guide bar on the upstream side is arranged on the upstream side of the fixed guide on the upstream side and at a position shifted upwardly by a sum of respective radii thereof, further, the guide bar on the downstream side is arranged on the downstream side of the fixed guide on the downstream side and at a position shifted upwardly by a sum of respective radii thereof.
By the constitution, the printing web passes to wrap on the respective fixed guides and the respective guide bars respectively over substantially 180 degree from the fixed guide on the upstream side to the fixed guide on the downstream side.
The two fixed guides are rotatably supported by frames provided on both sides in parallel with each other in the travelling direction of the printing web. Further, the two guide bars are supported by auxiliary frames provided on both sides in parallel with each other in the travelling direction of the printing web. By angularly displacing the auxiliary frames centering on fulcrums provided on the other side frame, the two guide bars are angularly displaced integrally with each other, thereby, adjustment of the side edge position of the printing web is carried out.
Next, according to the apparatus disclosed in Japanese Patent No. 2743200, a pair of side frames (fixedly supporting frames) are rotatably provided with a lower roller on the upstream side and a lower roller on the downstream side which are provided in parallel with each other at an interval of a certain distance therebetween in a travelling direction of printing web, further, on inner sides of the pair of side frames, there are provided a pair of auxiliary frames (pivotable frames) rotatably supporting an upper roller on the upstream side and an upper roller on the downstream side which are provided in parallel with each other at an interval of a certain distance therebetween in the traveling direction of the printing web. The lower roller on the upstream side is arranged on the lower side of the upper roller on the upstream side remotely therefrom, further, the lower roller on the downstream side is arranged on the lower side of the upper roller remotely therefrom.
By the constitution, the printing web passes to wrap on the respective upper rollers and the respective lower rollers respectively over substantially 90 degree from the lower roller on the upstream side to the lower roller on the downstream side.
Further, the pair of side frames are provided with a pivotable beam supporting the auxiliary frames, a stay (supporting horizontal member) supporting the pivotable beam and having a rotational center of pivoting thereof and a drive mechanism for driving the pivotable beam. By the drive mechanism, a side edge position of the printing web is adjusted by pivoting the auxiliary frames to thereby provide a certain angle to the upper roller on the upstream side and the upper roller on the downstream side with regard to a width direction of the printing web.
Further, there are provided a detecting apparatus having a sensor for detecting a displacement of the printing web in a transverse direction at a position of a longitudinal edge portion thereof, (that is, a displacement of side edge position) and generating an error signal at a vicinity of the lower roller on the upstream side, a correcting apparatus for correcting a position of the printing web at the longitudinal edge portion (side edge position) by pivoting the pivotable beam by a percentage equal to or lower than 100% of a pivotable limit of the pivotable beam, an apparatus of setting cautionary movement points constituting a pivotable upper limit and a pivotable lower limit at positions of percentages within a range of 100% of a total of a maximum pivotable displacement and a control,apparatus for generating a feedback signal when the displacement of the pivotable beam exceeds the cautionary movement points and correcting to adjust the position of the longitudinal edge portion (side edge position) of the printing web by roll stands of a paper feeding unit.
In the meantime, as an apparatus of adjusting a cutoff position, for example, an apparatus disclosed in Japanese Patent Publication No. Sho 52-10226 is publicly known. The apparatus is provided with a guide roller arranged such that printing web is made to wrap on the guide roller over substantially 180 degree of a peripheral face thereof and movably in parallel with the printing web in a travelling direction of the printing web which is made to wrap thereon by substantially 180 degree in a travelling path of the printing web and the cutoff position is adjusted by moving the guide roller in parallel with the travelling direction of the printing web to thereby change a travelling path length of the printing web.
Among the above-described publicly-known technologies, according to the apparatus disclosed in Japanese Patent Publication No. Hei 6-29108, when it is known that the travelling position of the printing web is shifted in the width direction, a hand-wheel provided at the frame on one side is rotated, and a machine frame (the above-described auxiliary frame) supporting a pair of movable guides is angularly displaced by an angle in accordance with a shift in the clockwise direction or the counterclockwise direction centering on the fulcrums provided at a vicinity of the frame on the other side.
Thereby, the shift in the width direction of the printing web is corrected and the printing web is returned to a predetermined travelling position.
However, at the frame on one side, the auxiliary frame is moved in a shape of a circular arc and accordingly, it is difficult to accurately install a member supporting the auxiliary frame and sticking or play is liable to cause. When the sticking or play is caused, there poses a problem in which much force is required in angularly displacing the auxiliary frame by rotating the hand-wheel.
Further, since there is constructed a structure in which the central point of the angular displacement of the auxiliary frame is provided at a vicinity of the frame on the other side and the auxiliary frame is supported by the pair of guide bars, in view of maintaining mechanical strength and accuracy, the auxiliary frame is necessarily constituted by a large-sized member, as a result, even in the case in which power is supplied in angularly displacing the auxiliary frame, large power is needed.
Further, with regard to printing web both faces of which are printed, abrasion is caused between the printing web and the movable guides and accordingly, there poses a problem in which print face is contaminated.
In the meantime, according to the apparatus disclosed in Japanese Patent No. 2743200, when the pivotable beam supporting the two movable rollers is angularly displaced, a portion of the pivotable beam remote from the central point of the angular displacement significantly protrudes on both sides of the stay and support of the pivotable beam by the stay becomes unstable. Therefore, not only operation of adjusting the side edge position of the printing web becomes difficult but also travelling of the printing web per se becomes unstable, as a result, there poses a problem in which adjustment of the side edge position cannot be carried out sufficiently.
Further, since there is carried out a control of adjusting the side edge position by providing a pair of sensors in the width direction of the printing web at an entry side of the web guide apparatus (that is, a vicinity of an upstream side of the lower roller on the upstream side constituting the travelling path of the printing web) and detecting the position of the edge portion in the longitudinal direction of the printing web (side edge position), there poses a problem in which the result of adjustment by the web guide apparatus cannot be detected.
Further, since there are provided the correcting apparatus, the apparatus offsetting cautionary movement points and the control apparatus for generating a signal when the displacement of the pivotal beam exceeds the cautionary movement points and correcting the position of the longitudinal edge portion (side edge position) of the printing web by the roll stands of the paper feeding unit, control and operation are doubled, the efficiency of operation of controlling the side edge position of the printing web is significantly deteriorated, further, the above-described amounts to an increase in the cost of fabricating the adjusting apparatus of this kind.
In the meantime, by the tendency of multiple color formation and multiple page formation of a rotary press in recent years, many facilities are concentrated on peripheries of a printing unit and a folding unit for realizing the multiple color formation and the multiple page formation and saving of space is ardently requested. Particularly, at a travelling path of the printing web from the printing unit to the folding unit, due to a necessity of adjusting a cut position of the printing web at the folding unit, a compensator roller apparatus (refer to FIG. 11) is provided and accordingly restriction of space is severe and it is extremely difficult to install to add the printing web
The compensator roller apparatus is for adjusting a length of a travelling path of the printing web and is constituted by an inlet side guide roller 82 (82a), a compensator roller 84 and an outlet side guide roller 83 in the traveling path of the printing web as shown by FIG. 11. The inlet side guide roller 82 guides printing web 21 to the compensator roller 84 on the downstream side. The compensator roller 84 provided movably in parallel with the traveling direction of the printing web 21, changes the traveling direction of the printing web by 180 degrees, guides the printing web to the outlet side guide roller 83 on the downstream side, further, the direction of the printing web is changed by the outlet side guide roller 83 again by 180 degrees to thereby return the traveling direction of the printing web to the original direction. By moving the compensator roller 84 in parallel with the traveling direction, in the case in which the printing web is cut at the folding unit on the downstream side, the cut position (cutoff position) is adjusted such that the printing web is prevented from being cut at a printed portion (printed image).
The present invention resides in providing an apparatus of adjusting a side edge position of traveling printing web resolving the above-described problems. Specifically, as follows.
A first object of the present invention resides in providing a printing web side edge position adjusting apparatus having a concise, simple and light-weighted mechanical constitution and smooth operation which is difficult to cause sticking or play.
A second object of the present invention resides in providing a printing web side edge position adjusting apparatus in which a constitution of control means is concise and control operation is swift and accurate.
A third object of the present invention resides in being capable of installing easily a mechanism capable of carrying out adjustment of a side edge position of printing web and adjustment of cutoff thereof between a printing unit and a folding unit while achieving space saving formation of facilities from the printing unit to the folding unit by adding a cutoff position adjusting function having a compensator roller apparatus in a printing web position adjusting apparatus.
A fourth object of the present invention resides in reducing or avoiding contamination of printing web caused by contact and abrasion between the printing web and guide bars which is produced when printing web both faces of which are printed passes through a printing web position adjusting apparatus.
In order to achieve the above-described object, the present invention is provided with a constitution, as a basic constitution, including:
two guide rollers provided orthogonally to a travelling direction of printing web and in parallel with each other; two guide bars disposed between the two guide rollers in a travelling path of the printing web, arranged such that the printing web from the guide roller on an upstream side of the travelling path of the printing web to the guide roller on a downstream side thereof, is made to wrap on peripheral faces of the respective guide rollers over substantially 180 degree and provided angularly displaceably in a plane in parallel with face of the travelling printing web respectively by separate angular displacement centers;
angularly displacing means for angularly displacing the two guide bars integrally with each other while maintaining parallelism therebetween;
an edge sensor disposed further downstream from the guide roller on the downstream side in the travelling path of the printing web such that a side edge position of the travelling printing web can be detected; and
control means for controlling operation of the angularly displacing means such that the side edge position of the printing web is adjusted to a previously determined position based on an output signal of the edge sensor.
Further, in order to achieve the above-described object, in addition to the above-described basic constitution, there is constructed a constitution in which at least one of the two guide rollers is provided reciprocally movably in parallel with the travelling direction of the printing web.
Further, in order to achieve the above-described object, there is constructed a constitution in which central portions of the two guide bars are made hollow and provided with small holes reaching hollow portions thereof at outer peripheral faces thereof on which the printing web is made to wrap, further comprising air supplying means for supplying compressed air to the hollow portions of the guide bars.